Optic Nerve Astrocytes (ONA)

Optic nerve astrocytes are the earliest glial population to emerge in the embryonic optic nerve, playing critical roles in retinal angiogenesis and the formation of the brain-retinal-barrier. As a major type of glia in the optic nerve, they perform multiple physiological functions, including potassium homeostasis and metabolism. These astrocytes are also essential for supporting retinal ganglion cell (RGC) axons and maintaining neuronal activity in the central nervous system. In response to injury or neurodegenerative insults such as glaucoma, optic nerve astrocytes undergo reactive changes—a process known as reactive astrogliosis—which can influence disease outcomes. Notably, astrocytes in the optic nerve are heterogeneous, exhibiting region-specific specializations between the optic nerve head and the myelinated optic nerve, and they contribute to axonal vulnerability through roles in mitochondrial turnover and energy provisioning.